• 한국정밀공학회지
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• 제23권3호
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• pp.147-155
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• 2006

High speed machining has become the main issue of metal rutting. Due to increase of the rotational speed of the spindle, problems, such as the run-out errors, reduced stiffness, must be overcome to improve the machining accuracy. In order to solve the problems, it is important to determine the appropriate clamping unit and tooling system. This paper presents an investigation into an evolution of contact interval which is the interface between spindle taper hole and tool holder shank of the spindle. Finite element analysis is performed by using a commercial code ANSYS according to variation of clamping forces and rotational speeds. This paper proposed fit tolerance in order to evaluate the effects of clamping force and rotational speed on the contact interval in the spindle interface. From the finite element results, it has been shown that the rotational speed rather than clamping force mostly influence on the variation of the contact interval.

• 대한한의진단학회지
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• 제9권1호
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• pp.131-135
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• 2005

Background and purpose: The measurement of direct current (DC) potential on skin area of meridian has recently been adopted to explore the electrophysiological characteristics of meridian system, But there exists two problems to be explained; the entity of the DC potential to be measured and the characteristics of electrode gel interface of measurement system, It is not clear whether the DC potential reflect, at least hypothetically, the entity of meridian, and if there exist any unstable factor in the DC potential measurement system. Methods: In this study, we designed an electronic circuit model of skin and applied known DC potential sources $({\pm}10.75mV,\;0mV)$ to the electrode interface of the skin model. Results: The result showed that the measured DC potential changed according to the time, and the same phenomenon was observed when the electrode gel was replaced with an electric condenser. It is suggested that the measurement of DC potential on electrode gel interface is very difficult and produces unstable values due to the capacity effect of electrode gel. Conclusion: Further studies on the DC potential evaluation in the context of meridian study should consider and bypass this problem.

• 컴퓨터교육학회논문지
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• 제18권1호
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• pp.35-43
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• 2015

텐지블 프로그래밍 도구는 그래픽 인터페이스 기반의 프로그래밍 방식과는 달리 컴퓨터를 사용하지 않고 손으로 조작하여 프로그래밍 할 수 있는 도구이다. 어린학생을 대상으로 알고리즘을 설계하고 시뮬레이션 하는 경험을 제공하여 논리적 사고 능력을 향상시킬 수 있다. 본 연구에서는 기존에 개발된 텐지블 프로그래밍 도구를 분석하여 도출된 문제점을 수정 보완하기 위해 다수의 명령어를 하나의 블록에 맵핑, 즉시적인 결과 확인, 다양한 수준의 알고리즘 표현이 가능하도록 설계 후 B-Bricks를 개발하였다. 개발한 B-Bricks를 초등학교 4-6학년 29명을 대상으로 적용한 결과, 문항의 난이도가 상승할수록 정답률이 감소하고 문제풀이시간이 증가하는 것으로 분석되었다.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2422-2430
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• 2020

In order to improve calculational efficiency of the CAPP code in the analysis of the hexagonal reactor core, we have tried to implement a refined AFEN method with transverse gradient basis functions and interface flux moments in the hexagonal geometry. The numerical scheme for the refined AFEN method adopted here is the response matrix method that uses the interface partial currents as nodal unknowns instead of the interface fluxes used in the original AFEN method. Since the response matrix method is single-node based, it has good properties such as good calculational efficiency and parallel computing affinity. Because a refined AFEN method equivalent nonlinear FDM response matrix method tried first could not provide a numerically stable solution, a direct formulation of the refined AFEN response matrix were developed. To show the numerical performance of this response matrix method against the original AFEN method, the numerical error analyses were performed for several benchmark problems including the VVER-440 LWR benchmark problem and the MHTGR-350 HTGR benchmark problem. The results showed a more than three times speedup in computing time for the LWR and HTGR benchmark problems due to good convergence and excellent calculational efficiency of the refined AFEN response matrix method.

• 디자인학연구
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• 제15권1호
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• pp.93-100
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• 2002

대학 web도서관은 web으로 도서관에 소장된 서지나 기타 자료의 검색, 대출, 반납에 관한 정보의 처리가 가능하도록 되어 있는 도서관의 형태이다. 정보화 사회에 진입 한 이후 네트워크와 멀티미디어란 것의 등장으로 인해 정보전달 및 획득의 수단과 과정에 있어서 엄청난 변화를 겪고 있다. 이미지 화, 동영상 화 된 방대한 멀티미디어 정보들이 네트 워크를 통해 정보 제공자와 정보 사용자간의 물리적 거리에 대한 한계를 느끼지 못하게 되었다. 하지만, 이에 따르는 문제점으로는 저작잔 인식부족, 인프라의 미비, 기술적, 신뢰성 등으로 인해 발전이 요구되는 상태이다. 본 논문에서는 국정 대학 평가 기준에 근거하여 20개 대학의 web기반 도서관 site에서, 각 시스템별 검색 형식과 user interface를 비교, 분석하였다. 이에 기초하여 web기반 대학 도서관의 실험적 user interface를 제작하고, 이 interface에 대한 설문조사 및 데이터를 수집, 정리, 분석하였다. 이 결과를 현재web기반 대학도서관의 일반검색 시스템의 인터페이스에 적용하여 도서의 위치, 도서의 대출 및 검색회수, 대학 web도서관 내에서의 도서구입에 대한 기능을 포함하는 새로운 user interface를 제안하였다.

• 한국전산유체공학회지
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• 제13권4호
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• pp.126-134
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• 2008

We developed a three dimensional Navier-Stokes code based on the level set method to simulate two phase flows with high density ratio. The Navier-Stokes equations with consideration of the surface tension effects are solved by using SIMPLE algorithm on a non-staggered grid. The present code is validated by simulating two test problems. First one is to simulate a rising bubble inside a cube. The thickness of the interface of the bubble is shown to affect the pressure distribution around the interface. As the thickness decreases, the pressure field around the interface becomes more oscillatory. As the bubble rises, a ring vortex is shown to form around the interface and the bubble eventually develops into an ellipsoidal shape. Merge of two bubbles inside a container is secondly tested to show the robustness of the present code for two phase flow simulation. Numerical results show stable and reliable behavior during the process of merging of two bubbles. The velocity and pressure fields around the interface of bubbles are shown oscillation free during the merging of two bubbles.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.49-51
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• 2005

Robot control involves advance programming, scientific and high technology. The systematic and methodological aspects of robot controls often results in having superficial control design problems that can negatively affect the robot application, usability and appeal. User friendly interface of robot control is extremely advantageous and more attractive. To illustrate, the application of medical robot is usually handled by clients who have little background in advance programming language. Thus, it would be difficult if the client needs to use programming language to control the robot. It would justify better if the robot control is presented in a meaningful interface to the client. This way the robot application would be more natural and user friendly. This paper describes the method of developing the user interface for web based communication to control an internet robot named Tarou. The web based communication tasks involves three levels. The first one accommodates on the client sending commands to robot through the internet. The next communication level relates to the robot receiving the commands sent by the client. The final communication level generates on sending feedback on status of commands by the robot to the client. The methodology used here can be elaborated in four hierarchical steps; identify user needs and robot tasks, identify the enhancing tag reference used by the server, induce the tag into HTML, present the HTML in attractive user interface as the client control panel.

• 대한기계학회논문집
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• 제17권2호
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• pp.359-370
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• 1993

Up to now, most studies are on interface crack problems in isotropic-isotropic dissimilar materials, but it seems to be not so much on anisotropic dissimlar materials. In this study, the stress intensity factors for an interface crack in anisotropic dissimilar materials are analysed using author's proposed extrapolation method by BEM and we have done a parametric study about material properties or shapes of crack affecting to the stress intensity factors. However, as there are not other's comparable numerical results on these anisotropic dissimilar materials to the best of author's knowledge, the reliability of the present results was proved by following two methods. The first is considering the asymptotic characteristic about stress intensity factors for an interface crack in anisotropic materials when the ansiotropic material approachs to the isotropic material. The second is considering the discontinuity of stress intensity factors between of a crack in an identical homogeneous anisotropic material and an interface crack in anisotropic dissimilar materials.

• 한국주조공학회지
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• 제31권3호
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• pp.124-129
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• 2011

We applied two numerical schemes to improve accuracy of the solution in the flow simulation of molten metal. One method is Piecewise Linear Interface Calculation (PLIC) method and the other is Donor-Acceptor (D-A) method. In the present work, we have tested simple problems to verify the module of the interface reconstruction algorithms. After validations, accuracy and efficiency of these two methods have compared by simulating various real products. On the numerical simulation of free surface flow, it is possible for PLIC method to track very accurately the interface between phases. PLIC method, however, has the weak point where a lot of computational time hangs, though it shows the more accurate interface reconstruction. Donor-Acceptor method has enough effectiveness in the macro observation of mold filling sequence though it shows the inferior accuracy.

• 한국주거학회논문집
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• 제27권1호
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• pp.63-70
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• 2016

Domestic apartment housing has been designed in accordance with the new housing supply-driven policies for a long time. As a result, its design, material production, construction, maintenance and remodeling process, rather than being systematically performed, were individually approached to cause insufficient linkage between technologies. For these problems and the supply of long life housing, active research on long life housing has been conducted in Korea since 2005. However, the existing research on long life housing has been focused on a single item with no connection made between infill systems, and no overall interface rule, resulting in no activation of the business. In this study, for the supply and activation of long life housing, we aim to analyze the problems of existing long life housing to set up its matching standards for infill systems.